Increase in temperature or Fever is one of the common side effects of immunisation. Give paracetamol every 6 - 8 hours for the 2-3 days. With respect to the poo, as long as the poo is normal and doesn't sink completely into the diaper then there is nothing to worry about.
Also, make sure you are checking the temperature of your baby using a thermometer.
Also, make sure you are checking the temperature of your baby using a thermometer.